Vibratory compactors are routinely used in the construction industry and the like to compact soil or other work surfaces. These are often attached to mobile machines that include a cab that houses an operator that controls the operation of the vibratory compactor. These compactors often include a vibration mechanism such as an eccentric device that causes a plate to move up and down in a rapid or vibratory manner to effectuate the flattening of the work surface. The vibration mechanism is often hydraulically powered.
In many applications, the eccentric device includes an eccentric mass that is coupled to a shaft, which creates the desired vibrations. It is often desirable to start compacting loose dirt using low frequency and high amplitude oscillations while it is more desirable to progress to a higher frequency lower amplitude over time to produce soil that is tightly compacted.
Looking now at FIG. 1, a perspective view is shown of a machine 100 using a vibratory plate compactor assembly 200 according to a prior art design used to compact soil 128. The machine 100 that is compatible with a vibratory plate compactor assembly 200, that is to say, a coupling device 102 is provided so that the vibratory plate compactor assembly 200 may be attached to the machine and be controlled by the machine 100. In this embodiment, the coupling device 102 is located at the free end 104 of the boom 106 opposite the end 108 of the boom 106 that is attached to the turn table 130 of the machine 100. The machine 100 further comprises a controller 110, a motor 112, a wheel or track undercarriage 114 that is driven by the motor 112, and the vibratory plate compactor assembly 200 that is attached to the boom 106 of the machine 100 using the coupling device 102 as already mentioned. The controller 110 is in communication or operative association with the controls 116 provided in the cab 118 so that the operator may control the movement and function of various parts and systems of the machine 100.
More specifically, the machine 100 depicted in FIG. 1 is a large excavator but it is contemplated that other machines such as backhoes and the like could also use a vibratory plate compactor assembly 200 according to any embodiment of the present disclosure. Furthermore, the machine 100 is mobile on a track driven undercarriage 114 but a more conventional wheel or tire type undercarriage may also be used that is powered by the motor 112. For this machine 100, the motor 112 comprises an internal combustion engine but other motors such as an electric motor could be used for other embodiments. In addition, hydraulic hoses 120 connect the cylinders 122 that move the linkage members 124 of the boom 106 to a hydraulic manifold 126. Similarly, hydraulic hoses 120′ connect the vibration mechanism 202 of the vibratory plate compactor assembly 200 to the manifold 126 (shown in hidden lines). A hydraulic pump (not shown) provides the hydraulic fluid necessary to rotate or otherwise drive the eccentric mechanism 204 that is part of the vibration mechanism 202. The movement of the boom 106 and powering of the vibration mechanism 202 may be achieved by other devices or methods in other embodiments such as by mechanical or electrical power, etc.
Turning now to FIG. 2, the coupling device 102 that connects the vibratory plate compactor assembly 200 to the machine 100 can be seen more clearly as well as the hydraulic hoses 120′ that connect the vibration mechanism 202 to the hydraulic manifold 206 (shown by hidden lines) of the assembly 200 and system of the machine via hoses 120. The assembly includes an adapter subassembly 208 that is attached to the top plate 210 of the assembly 200 using fasteners, welding, etc. The adapter subassembly 208 includes a first side plate 220 with two ear portions 212 that define pin receiving bores 214 and a second side plate 216 with two ear portions 218 that define pin receiving bores that are aligned concentrically with the pin receiving bores 214 of the first side plate 220. Only one side may be clearly seen as the other side is obstructed by the boom 106 of the machine, but it is to be understood that both sides may be similarly constructed. Pins 222 that are part of the coupling device 102 of the machine extend through the bores 214 to hold the adapter subassembly 208 and vibratory plate compactor assembly 200 to the boom 106 of the machine 100. In some embodiments, the coupling device 102 may be a quick change coupling mechanism but this might not be the case for other embodiments. In some cases, the assembly 200 may be permanently attached to the machine 100.
Now referring to FIGS. 2 and 3, the vibratory plate compactor assembly 200 comprises an upper portion 224, a lower portion 226 that is movably attached to the upper portion 224 and that includes a compacting plate 244, a vibration mechanism 202 operatively associated with the lower portion 226 for vibrating the lower portion 226, a plurality of isolation mounts 240 and a hydraulic hose 120′ that runs from the manifold 206, which is attached to the remote side of the upper portion 224 of the compactor 200 that does not move, to the vibration mechanism 202 that is on the lower portion 226 of the compactor 200 that does move. The vibration mechanism 202 is supported in the bores of the support plates 230 of the lower portion 226.
As mentioned previously, it is desirable to adjust the type of vibrations provided by the compactor plate. This prior art device just described lacks this ability. One method of adjusting the vibrations is to move the eccentric mass further or closer from the rotating shaft so that the amplitude is adjusted. Preferably, the mass is initially farther from the shaft at low speeds and closer to the shaft at higher speeds. Currently, complex mechanical or electrical systems may be able to achieve this but it is desirable to adjust the position of the eccentric mass using only the shaft speed if possible without use of complex mechanical or electrical systems.